This paper presents a biogeochemistry dataset derived from the French component of the PIRATA (Prediction and Research Moored Array in the Tropical Atlantic) program in the Gulf of Guinea. This program, which started in 1997 with the deployment of a buoy network, has offered the opportunity to collect seawater biogeochemistry parameters since 2004. The measured parameters include salinity, dissolved oxygen, nutrients (since 2004), phytoplankton pigments (since 2011), marine pH (since 2021) and total alkalinity (since 2023). Following rigorous procedures, we provide high-quality data for studying the spatial and temporal variability of these parameters, with the aim of gaining a better understanding of the underlying processes that drive the ocean’s biogeochemical cycles in the Tropical Atlantic. The data are available in the SEANOE repository, which is accessible for scientific data in the marine sciences.